1. Field of the Invention:
This invention concerns improvements in or relating to load supporting roller assemblies of the kind that are used for engagement with a track or rail to permit movement of a heavy element carrying the roller relative to the track. In particular, but not exclusively, this invention has application for supporting a door or window for sliding movement along a rail.
2. Description of Prior Art:
It is already known to provide roller assemblies that are like wheels having some form of axle for mounting the wheel for rotation. It is also known to provide wheels having specially shaped rims, or even tyres for location on a rail or track. It is also known to provide roller assemblies made of various materials to resist wear and to reduce friction. However, the known type of roller assembly usually suffers from one distinct disadvantage when used for supporting a heavy element, and this is that there is only a very small area of contact with the rail or track through which the load and pressure is exerted. This load and pressure means that wear and distortion occurs both in the roller and the track, and even the provision of a tyre or special track or rail cannot obviate this in many cases without making the eventual assembly too cumbersome, or too expensive, or even so complex that repair or replacement is impractical.